Tranny Problems

I'm rebuilding a Spicer transmission (for Bunton / 5 speed) for about the 5th time in 2 years. The lower bearings keep failing on the input shaft - causing the pinion gear to wear and ultimately fail too. Does anyone have any experience here? I'm looking for a trick to help me keep these bearings from faliure (better lubrication!). I think it's just a bad design prob - but if any fellow Lawsnite Mechanics have any suggestions - i'd sure appreciate it. At present, the only change I'm thinking of making on this rebuild is to use a high grade synthetic grease (instead of the standard gen purpose stuff).

I think I've had the same problem on my Byers Gold. I'm trying to go on memory here so please bear with me.

On that lower bearing there are two "O" ring seals. One on the bottom, under the lower bearing, and one on top of that lower bearing.

It seemed to me that top "O" ring only kept the bearing from replenishing itself with grease from the gear case.
So when I replaced the bearing, I took the top "O" ring out. Never had any more trouble, and it's been a year.
This may not be what you're talking about at all but if it is, I hope this helps.